Cranfield University

Field Study With Full Size Combine Harvesters
type, e.g. on the subsoiled plot the tyre and the tyre at high inflation pressure were statisti-
cally the same concerning the average rut depth. Hence, an analysis of variance was carried
out with the parameters tyre, soil and tyre soil interaction to ease the comparison of differ-
ent treatments when looking at Table 17. All three parameters were significant and the
results in relation to the measured parameters and statistical differences amongst treat-
ments and amongst soil types are shown in Table 18 and Table 19, respectively.
Table 16: Rut parameter field trials including all treatments
Treatment Aver. Max Depth (mm) Aver. Aver. Depth (mm) Aver. Width (mm)
Subsoiled Track 1 90 55 920
Subsoiled Track 2 102 70 903
Subsoiled Tyre 1 112 80 873
Subsoiled Tyre 2 120 103 907
Subsoiled High 152 100 953
Shallow Track 1 48 20 670
Shallow Track 2 50 18 790
Shallow Tyre 1 43 23 873
Shallow Tyre 2 63 47 810
Shallow High 73 55 830
Clay Track 1 55 25 857
Clay Track 2 60 35 860
Clay Tyre 1 82 63 850
Clay Tyre 2 88 52 830
Clay High 105 82 830
All treatments are significantly different with regard to their maximum rut depth and aver-
age rut depth, however, average rut width was the same for all treatments. The significant
difference in maximum rut depth and average rut depth in the field experiments confirmed
the results from the soil bin.
As soil displacement, soil density and penetrometer resistance were mainly influenced by
rut depth, this clear result put emphasis on the differences seen in penetrometer resistance
and soil displacement.
Ph.D. Thesis Dirk Ansorge (2007)
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